Air compressor



May v6., 1930.

Filed June 2, 1927 as so 3 l22 e! 31s i 34 31 if 4 15 Q 4a 4e 4* g s1l 4'! 17 l ss //zesaes 2 Sheets-Sheet 1 fau f naar May 6,1930. R. P. PESCARA AIR' COMPRESSOR Filed June 2. 1927 V2. snets-sheet 2 'Patented May 6,1930

UNITED sTATEs mur.. rArEnAs PESCARA, or rAnIs, FRANCE Am conrnnsson `Application led June 2, 1927, Serial No. 195,980, andin France .Tune 5, 1926.

My invention relates to improvements in air compressors in which the compression takes place in stages and the principal ob.- ject is to establish a combination of compressing cylinders and pistons arranged in such a manner as to produce a high output and hi h compression of the gases to be compressed.

A further object of the invention is the adaptation of`such an arrangement to the compressors forming the subject of'invention of my French Patents No. 627,385, of April 1, 1926; No. 627,366,0f Apri12, 1926; No. 626,982, of April 7, 1926; No.- 628,550,

of April 8, 1926; No..628,563, ofv April 9,

1926; and N0.- 628,572,016 Api-i1 1o, 1926.

Still anotherobject of the invention is to arrange the parts so that the independent spaces in which the expansion and'compression of an inert gas produces" stability of operation -of the apparatus, as setv forth in.

the fourth of my French patents above men- I tioned, if desired, and to utilize the' dead space of the cylinders of one of the stages of compression for producing the same result, the principle of which is more fullyA ries of compressing cylinders, whose bores become less from the center of the apparatus toward the extremities thereof, in conjunction with two direct-acting pistons, corresponding 011 the one hand to the successive on the other hand adapted to receive a driving impulse in a centrally disposed cylinder common thereto. These various features are so arranged in combination that the said pisducing' compression of the gases in two se tons remain completely free of all mechanical transmissiondestined to transfer the driving energy, with the exception of that which is required for the operation of the accessories of the machine, such as, distribution, l.ignition andthe like all of which is more fully disclosed in the French patents,

above pointed-out, and to which reference may be had for a fuller description. i

Referring to the drawing, and particularly to Fig. 1, a central motor cylinder 12 has' disposed in` axial alignment at each end thereof a pair of low pressure compressing cylinders 13 and 14, a pair of medium or mean pres-'f sure cylinders 15 and 16 disposed in axial alignment with and at the ends of said cylinders 13 and 14 anda pair of high pressure compressing cylinders 17 and 18 disposed in yaxial alignment at the extremities of said cylinders 15 and 16.

A multiple pistonis adapted to slide in each series of cylinders and the central motor cylinder 12. These pistons comprise a cylindrical portion 19 and 20 fitted in motor cylinder 12,' a portion 21 and 22-tted in the low compression cylinders 13 and'14, a portion 23 and 24 tted in the medium' compression cylinders 15and 16 and aj portion 25 and 26 l'itted `in the high compressing cylinders 17 and 18, respectively.

The motor cylinder 'l2 is furnished with admission openings27 and exhaust openings 28 in order to accomplish the necessary two cycle combustion operations in said cylinderl as more fully disclosed in my'French Patent No. 626,928 of April 7, 1926, above referred to.

The pistons 21, 22 compress the air drawn into cylinders v13 and 14 through valves 29 and 30 from the atmosphere and push it back through the valves 31 and 32 into a low pressure tank 33. In passing into the' said tank this air circulates through tubes 34 and 35 then ythrough coolers 36 and37 respectively which restores its initial temperature before entering the tank 33 through tubes 38 and 39. bores of the said compressing cylinders and In like manner the pistons 23 andA 24 compress the air drawn into the cylinders 15 and soA 16 through the pipes 40 and 41 from the low pressure tank 33 passing throughcheck valves 42, 43 provided-for that purpose. The air mixture i then circulates through check valves 44 and 45, tubes 47 and 48, coolers 49 and' 50 for restoring its initial temperature, pipes 51 and 52 and nally enters the medium pressure tank 46.

The pistons 25 and 26 compress the air drawn intovcylinders 17 and 18 through pipes 53, 54 from tank`46 through check valves 55 and 56 and drive it through the valves 58 and 59 'through tubes 6 0 and 61 and finally into the high pressure tank 57. v

It is thought that a further detailed description of the operation is unnecessar in view of the disclosure of the patents, a ove referred to. The only difference it presents over the operation described therein is the mannerof stabilizing the machine which is substantially the same for the compound compressor forming the subject of this application.

When the pistons 19, 21,23, 25 and 20, 22,

v24, 26 reach the end of .their compressing power stroke, they stop in a position which is substantially that represented in Fig. 1. Their return stroke and the achievement of the engine cycles in cylinder 12, namely the preliminay com/pression of the ex losive motive forces; first, the expansion of the compressed gaseous cushions remaining` at the end of the stroke in the en'ds 62, 63, 64, 65, 66,

67 of the respective compressing cylinders 13,

`No. 628,550 of A ril 8, 1926, above mentioned,

in order to. stabl ize the apparatus, it is necstroke so as to overcome the inevitable variations which can take place in the energy transmitted or received by the pistons 19,21, 23, 25 and 2o, 22, 24, 26.

In the present apparatus this compensation can be obtained through the medium of the gaseous cushions contamed the" spaces 62, 63, 64, 65, 66, 67. It will be noticed, however, that'the check valves 58 and 59 vof the high pressure cylinders 17 and 18 are dlsposed on the lateral wall thereof instead of the disposition disclosed 'in connection withthe other cylinders and check valves, 1n such a manner that the orifices which the control are covered in the event that the pistons 25, 26 move beyond their normal forwardstroke and lass their theoretical dead points.

Li ewise as has beenv disclosed in my c opending application just referred to, 1t wlll said cylinder is assured y two.

' essary to establish a compensation betweenu lthe different motive forces during the return be remembered that an anomaly altering i .for disturbances causing too long a stroke as well as those causing too short a stroke.

If said pistons pass the dead point as shown in Fig. 1 they will only be returned by dimin,

ished air cushions in spaces 62, 63 and 64,

65 the volume of which becomes smaller and the pressure of which remains constant. The .air cushions in spaces 66 and 67 will always incl e the same mass of air inasmuch as the pistons 25 and 26 will have covered up the `check valves. On the other hand the pressure of the air contained in the said spaces will have increased and will furnish energy in expanding superior to that normally produced. -It wilLthus be seen that partial compensation can take place 'between the diminu-l tion of the cushions in spaces 62, 63 and 64, 65 and the enrichment in energy of the air cushionsin the spaces 66, 67 This compensation effectively assures the return to normal operation at the end of a small number of reciprocations as soon as the abnormal stroke disappears.

The embodiment shown in Fig. 2 is similar to that described in connection withvFig. 1 l and provides for the case where'the bore of the motor cylinder must be larger thanthat of the compressor cylinders of the first stage.

In order to facilitate a ready com arison between the two embodiments the e ements of Fig. 2 corresponding to those of Fig. 1 have been' given the same numbers of reference increasedfby 100. v

It is thought that a detailed description is unnecessary due tothe similarity of the two devices. Suiice it `to say that the chief difference between the two embodiments resides solely in the disposition of pistons '121, 122 corresponding to the first stage of com-4 pression in concentric relation with respect to-motor pistons119, 120 as pointed out in my French Patent No. 627,386 of April 2, 1926 above referred to in connection with a simple compressing apparatus.

in connection with Fig. 1 with the exception that the check valves 158, 159 are disposed in' the cylinder heads of high pressure hylinders 117, 118 and independent gaseous cushions are established by means of the annular spaces Many variations in my apparatus may be made by those skilled in the art without departing from my invention, since Stabilization isaccomplished as 4described n lill) .Y What Iclaim is 1. In a'. compound air compressor of the type described, the combination of a motor cylinder, a plurality of compressingcylinders of different diameters mounted coaxially with said motor cylinder at each extremitythereof a multiple direct-acting free-iiying piston tee-d in each extremity of said motor cylinder' andV extending. into said compressing cylinders and means associated with said compressing cylinders for 'producing compression in stages.l b Y 2. In a compound air lcompressor of the type described, the combination oa motorcylinder, a plurality of compressing cylinders of different diameters mounted coaxially with said motor cylinder'at each extremity thereof, a piston'dis osed in each extremity of-said motor cylin er,'s'aid motor cylinder having a plurality ofadmissio'n openings and a plurality of exhausglopenimgs whereby said pistons may ber driven directly by means of internal combustion, a uralityof compress- 'ing pistons integnahwith each of said rst mentioned pistons. and extending into said compressing cylinders and means associated with said compressing cylinders for producing compression in sta es;

3. In a compound airconipressorl of t i type described, the combination of a plurali of driving pistons adapted to be driven directly by means of internal. combustion, a common cylinder for said driving pistons, a plurality of series, of low, medium, and high pressure cylinders connected-to said motor cylinder, a plurality of series .of corresponding pistons mounted in saidi compressing cylinders, a low pressure tank and means for connecting it to said low pressure. and said y medium pressure cylinders, a. medium pressure tank and means for connecting it to said medium pressure and said high pressure cylinders, a high pressure tank and means for connecting it to said high pressure cylinders and means associated with said tanks andA said compressing cylinders for allowing -airv to be-drawn invfrom the atmosphere pushed through said compressing cylinders and said tanks and compressedn stages.

4. In a compoundfair compressor of the type described, the combination of a'pair oi compressing pistons, means for driving'said pistons directly by means of internal combustion, including a motor cylinder common to said pistons, said motor cylinder having ar plurality of inlet openings and a pluralityof exhaust openingsl and means cooperating4 with said compressing pistons for producing compression in stages and automatically stabilizing-the operation of said pistons.

5. In a compound air compressor ofthe typedescribed, the combination of a pair of compressing pistons each' comprising four cylindrical portions of diierent diameters, a common motor cylinder for two of said cylin- 'drical portions, said -motor-cylinder having a plurallty of inlet openings and a plurality of lecting the gas thus compressed, said valves being adapted to be covered and rendered ineffective near the end of the stroke of said pistons whereby the operation of the device is ,automatically stabilized. A 6, In a compound air compressor of the type described, the combination of a motor cylinder, a plurality of compressing. cylinders of different diameters mounted coaxially with said motor cylinder at each extremity thereof, a piston disposed in each extremity of said motor cylinder, a plurality of compressing pistons integral with each of said rst mentioned pistons' and extending into said com`- pressin cylinders, Lindependent stabilizing means or each of s'aid first mentioned pistons and means associated with said compressing cylinders for producing; compression in stages. v

7. In a compound'air-compressor .of the type described, the-combination of a motor cylinder, a plurality of compressing cylinders of different diameters mounted concentrically 295 t with said motoi` cylinder at each extremity thereof', va piston disposed in eachy extremity of said motor cylinder, said motor cylinder having a plurality'oi admission openings and a plurality of exhaust openingswhereby said pistons may be driven directly by means of internal combustion, a plurality vof corn-l pressing pistons integral with each of said first mentioned pistons and'extending into said compressing cylinders, independent stabilizing means for each. of said first menfv -tionedrpistonsY and means associated with said compressing cylinders for producing v compression iii-stages'. v

8.- In 'a compound air compressor of the type described, the' combination of a pair of compressing p1stons,"means'for. driving said pistons directly by means off internal combustion, including a motor cylindercommon to 'said pistons said motor cylinder having a 1120 pressing pistonsfffor producing compression In testimony whereof I have fsigned my'f-.

name to this specificationv at ,@,I'SLF T3110?" this 21st dag of Ma, 1927.

, l .5125 TERAsP-ESCARA; 

